Modern graphics hardware commonly use anti-aliasing techniques to minimize or smooth out aliasing artifacts that are often manifested as the jagged appearance of edges on image objects. One method of anti-aliasing is supersampling, which generates an image at sub-pixel resolution and averages the color intensity on each pixel region. The multiple color samples within the image are averaged out or downsampled. Multisample anti-aliasing (MSAA) is a special case of supersampling, which renders as much of the scene as possible without using anti-aliasing, but processes extra samples of the pixels on the edge of the object where aliasing artifacts are typically more pronounced. MSAA represents an optimization of supersampling in that the renderer evaluates the fragment sample once per pixel and only supersamples certain components of the final image. Additionally only some fragments undergo this partial supersampling and the resulting pixel storage may represent a complex multisampled pixel or a single sampled pixel. MSAA is typically used in real-time rendering solutions to avoid the overhead imposed by supersampling, which is more costly due to performing multiple shading operations for every pixel in the image regardless of the contents of the image.
The advent of high-resolution displays (e.g. Eyefinity systems with multiple monitors, or Retina® displays on low power devices) incur a very high cost for pixel processing (e.g., shading or coloring) due to the very large number of screen pixels. This cost may be out of proportion to the performance capabilities of the graphics rendering device. For example, shading operations can be very costly for each pixel since they typically require a large amount of power in terms of both processing and energy cost. The new high-resolution displays generally have a pixel density that is high enough (e.g., on the order of about 300 or more pixels per inch) that some claim a person is unable to discern the individual pixels at a normal viewing distance. To address the challenges posed by such displays, present solutions typically involve rendering at a reduced resolution and then upscaling to a final target or native display resolution. Such solutions are often undesirable, however, due to the introduction of scaling artifacts, and other distortion effects. Though an upscaling filter can be used to help alleviate these problems, such filters are typically quite complicated and can incur a high cost to produce reasonable image quality.
The demands of increasing display resolution in new high-resolution displays also requires increased pixel fill. As these displays push resolution beyond perceptible levels in many portions of the display, they create the added need to perform pixel fill uniformly over the entire display area to meet minimum resolution requirements.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches.